title: Identification of egg-jelly substances triggering sperm acrosome reaction in the newt, Cynops pyrrhogaster.
abstract: Our previous studies have shown that the acrosome reaction (AR) occurs in egg-jelly of the Japanese newt, Cynops pyrrhogaster. This is analogous to the substances of echinoderms but distinct from those of many other vertebrates derived from the egg envelope or its derivative, the zona pellucida. To identify the AR-inducing substances in newt egg jelly, a monoclonal antibody (mAb) was generated against the jelly by screening the culture supernatants to find the one that best neutralized the AR-inducing activity of the jelly substance. The mAb specifically reacted to protein bands in the jelly. These proteins, with apparent molecular weights of 122 and 90 kDa, exhibited AR-inducing activity, indicating that they are definitely AR-inducing substances. Western blotting using the mAb indicated that the 122 and 90 kDa proteins are present only in the egg jelly's outermost layer, where AR-inducing activity is known to occur. Both proteins were recognized with wheat germ agglutinin (WGA), a lectin that inhibits AR-induction in egg jelly extract. Taken together, these findings indicate that the 122 and 90 kDa proteins are the AR-inducing substances in the egg jelly of C. pyrrhogaster. The WGA recognition of the proteins was lost by N-glycosidase digestion, suggesting that N-linked carbohydrate moieties in these proteins may be responsible for the AR-inducing activity.
authors.affiliation: Faculty of Science, Department of Biology, Yamagata University, Yamagata, Japan. watan@sci.kj.yamagata-u.ac.jp
authors.forename: Akihiko
authors.initials: A
authors.lastname: Watanabe
authors.forename: Keiko
authors.initials: K
authors.lastname: Fukutomi
authors.forename: Hideo
authors.initials: H
authors.lastname: Kubo
authors.forename: Manami
authors.initials: M
authors.lastname: Ohta
authors.forename: Eriko
authors.initials: E
authors.lastname: Takayama-Watanabe
authors.forename: Kazuo
authors.initials: K
authors.lastname: Onitake
mesh_terms: D020101:Acrosome Reaction / Q000502:physiology*; D000818:Animals; D002241:Carbohydrates / Q000737:chemistry; D005260:Female; D008297:Male; D010063:Ovum / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D012455:Salamandridae; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*
chemical_list: D002241:Carbohydrates